Children with acute diarrhea who came to 2 public hospitals (Joao Alves Filho and Municipal da Zona Norte) and 3 health centers that provided health services to a population (Santa Maria) in Aracaju, Brazil, were enrolled from November 2006 to February 2007. Children who came to the hospitals were enrolled consecutively on specific days of the week by study health workers, and children who came to the health centers were visited at home after we checked the daily attendance lists of the centers. Acute diarrhea was defined as any episode <14 days duration with >
3 watery stools per day. Background and clinical information were collected after obtaining parental consent, and stool samples were stored frozen in duplicate at –80°C until analyzed in Liverpool, UK. Information on rotavirus vaccination was obtained from parents and cross-checked against vaccination record cards. A child was considered vaccinated if 2 doses of the vaccine had been recorded on the vaccination card. Rotavirus detection, genotyping, electropherotyping, isolation of strains in cell culture, and sequencing were performed as described (7
). Severity of diarrhea episodes was classified according to a modified Vesikari score (8
). Data were analyzed by using descriptive statistics in Epi-Info 2002 (Centers for Disease Control and Prevention, Atlanta, GA, USA). The study protocol was reviewed and approved by the Ethics Committees of the Liverpool School of Tropical Medicine and the Federal University of Sergipe.
A total of 129 patients with a median age of 12 months (range 1 month–12 years) were enrolled. Of these, 63 (49%) were <1 year of age, 39 (30%) were 1–2 years of age, and 27 (21%) were >2 years of age. A total of 21 children (16%) were positive for rotavirus by ELISA. Of these children, 20 were identified among 89 children enrolled in the hospital and 1 was identified among 40 children enrolled in the health centers (p = 0.002). Forty-eight children (37%) had received the rotavirus vaccine. The frequency of rotavirus infection by vaccination status and age is shown in the . Among children <1 year of age, 3 (7%) of the 44 vaccinated children were infected with rotavirus compared with 5 (26%) of 19 children who did not receive the vaccine (p<0.05). Among children 1–2 years of age, 4 had received the vaccine and 1 (25%) of them was infected with rotavirus compared with 8 (23%) of the 35 children who did not receive the vaccine (p not significant).
Frequency of rotavirus infection by vaccination status and age, Aracaju, Sergipe, Brazil*
The median (range) diarrhea severity scores of children with and without rotavirus infection were 12.9 (10–15.8) and 9.4 (5.3–13.5), respectively (p<0.001). Although numbers are small, vaccinated children had a median (range) diarrhea severity scores of 12.5 (7–15) if they were infected with rotavirus and 7 (3–17) if they were not infected. Similarly, the median (range) severity scores for unvaccinated children were 13 (8–15) and 11 (4–14) for children with and without rotavirus infections, respectively (p not significant).
All 21 rotavirus infections were with genotype PG2. One child had a mixed infection with PG2 and P[NT]G9. Nineteen specimens had short electropherotype strains, 1 was positive but with an undefined pattern, and 1 had insufficient RNA to produce a pattern.